Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis.
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PMID:Pharmacological studies of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate. Effects on experimental pancreatitis. 209 32

Intact erythrocytes of different Rh genotypes were subjected to various enzyme treatments, the effects of which were monitored by separating the membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and performing Western blotting using an antibody preparation that recognizes only Rh-related polypeptides. We found that treatment of intact cells with either phospholipase A2 or proteases such as papain did not alter the size of Rh antigen-containing polypeptides. In contrast, phospholipase A2 treatment followed by papain digestion cleaved a fraction of these polypeptides. This cleavage appears, from such digestions of Rh(D) positive and negative cells of different genotypes, to occur solely at the extracellular domain of Rh(D) polypeptide, while the extracellular domains of other Rh antigen-containing polypeptides are unaffected. Digestion of red blood cell ghosts and inside-out vesicles with trypsin showed that Rh(D), (C/c), and (E/e) antigen-containing polypeptides span the lipid bilayer having cytoplasmic domains susceptible to the action of proteases. The size of the cleavage products at the cytoplasmic domain of -D-/-D- cells was found to differ from that of other Rh(D) positive genotypes, due possibly to a difference in folding of Rh(D) polypeptide at its cytoplasmic domain and within the cellular membrane of these cells.
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PMID:Enzymatic evidence for differences in the placement of Rh antigens within the red cell membrane. 210 64

The kinetic properties and inhibitor sensitivity of human sperm phospholipase A2 (PLA2; EC 3.1.1.4) were studied. Phospholipase activity was isolated from human spermatozoa by acid extraction. Hydrolysis of dipalmitoyl phosphatidylcholine was specific to the sn-2 position. Activity was sensitive to product inhibition (60% inhibition by 0.1 mM lysophosphatidylcholine). The effects of Ca2+ and sodium deoxycholate on enzyme activity were biphasic; maximal activities were observed at 0.5 mM concentration of each agent. PLA2 was stimulated (135%) by 3% dimethylsulfoxide and was inhibited by elevated ionic strength (approximately 70% inhibition with either 0.2 M NaCl or 0.2 M KCl). Two molecular forms of PLA2 were kinetically distinguishable, one with an apparent Michaelis constant and maximal reaction velocity of 3.0 microM and 0.64 mlU/mg protein and the other with respective constants of 630 microM and 32.0 mlU/mg protein. Both forms of the enzyme were Ca2+ dependent and heat stable; however, the low-Km activity was less resistant to 60 degrees C preincubation at pH 7.5 (28% inactivation of low-Km activity after 45 min, as compared to no effect on high-Km activity). Quinacrine was a noncompetitive PLA2 inhibitor with Kis for low- and high-Km activities of 0.42 mM and 0.49 mM, respectively. Trifluoperazine (calmodulin antagonist) inhibited the high-Km activity noncompetitively (Ki = 87 microM) and the low-Km activity by a mechanism consistent with the removal of a nonessential activator. Dissociation and rate constants for inactivation of low- and high-Km activities by p-bromophenacyl bromide were 0.28 mM and 0.032 min-1, and 0.73 mM and 0.066 min-1, respectively. PLA2 was inhibited by p-nitrophenyl-p'-guanidinobenzoate, at higher concentrations (10(-4)-10(-3) M) than required to inhibit trypsinlike proteinases; p-aminobenzamidine, another potent trypsin/acrosin inhibitor, stimulated (approximately 40%) PLA2 at concentrations from 2-5 mM but inhibited PLA2 (40-50%) at a concentration of 10 mM. MnCl2 (5mM) inhibited low- and high-Km PLA2 activities by 77% and 76%, respectively. Quinacrine (0.4 mM), trifluoperazine (20 microM), p-bromophenacyl bromide (20 microM), and MnCl2 (5 mM) were tested as inhibitors of the ionophore A23187-induced human acrosome reaction. Inhibition was noted only with quinacrine (32%) and MnCl2 (93%). The effect of MnCl2 was restricted to an interaction with A23187, rather than with PLA2; p-Bromophenacyl bromide inhibited (P less than 0.05) PLA2 (29%) when added to intact spermatozoa but had no effect on the acrosome reaction. PLA2 inhibition was poorly correlated with the acrosome reaction.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Characterization and inhibitor sensitivity of human sperm phospholipase A2: evidence against pivotal involvement of phospholipase A2 in the acrosome reaction. 226 93

Crotoxin is a neurotoxic phospholipase A2 capable of blocking synaptic transmission by inhibiting the release of neurotransmitters. The photoaffinity labeling technique was used to identify the neural membrane molecules involved in the binding of crotoxin. A photoactivatable, radioactive derivative of crotoxin was synthesized by reacting crotoxin with N-hydroxysuccinimidyl-4-azidobenzoate and with Na[125I]. Photoirradiation of synaptosomes from guinea pig brains in the presence of the crotoxin derivative resulted in the formation of a major radioactive conjugate of 100,000 daltons as revealed by autoradiography of a sodium dodecyl sulfate-polyacrylamide gel electrophoretic pattern. Pretreatment of the synaptosomes with trypsin, Staphylococcus aureus protease, or papain prevented the formation of this conjugate. The conjugate was not detected when plasma membranes from several nonneural tissues replaced the brain synaptosomes. Unmodified crotoxin inhibited the formation of this adduct with an IC50 of about 10(-8)M. Mojave toxin, caudoxin, notexin, Naja naja PLA, and taipoxin also inhibited adduct formation with different potencies, while beta-bungarotoxin and pancreatic PLA were ineffective. We concluded that an 85,000-dalton protein is the major component responsible for the binding of crotoxin to synaptosomal membranes.
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PMID:Identification of a crotoxin-binding protein in membranes from guinea pig brain by photoaffinity labeling. 234 82

In patients with pancreatic cancer deoxyribonuclease I (DNase I) serum levels were compared with those of other known pancreatic enzymes. Serum deoxyribonuclease I, elastase 1, immunoreactive trypsin, amylase and phospholipase A2 were determined in 40 healthy controls, 28 patients with pancreatic cancer, 49 with chronic pancreatitis and 40 with extra-pancreatic diseases. The analysis of variance showed a significant difference among groups for serum DNase I values. However, none of the 3 groups of patients had a mean deoxyribonuclease I value higher than that of the healthy controls. In pancreatic cancer and chronic pancreatitis patients, increases in the 4 pancreatic enzymes values were found in percentages that were higher than those for DNase I. A significant correlation was found between DNase I and phospholipase A2, but not between DNase I and elastase 1, immunoreactive trypsin and amylase serum activities. The findings indicate that deoxyribonuclease I serum determination is an even less satisfactory index of pancreatic malignancy than the other pancreatic enzymes. Rather than expressing pancreatic damage, any variations in this enzyme appear more likely to reflect an aspecific phenomenon.
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PMID:Deoxyribonuclease I serum activity in pancreatic cancer. 235 55

Morphological features of Manduca sexta plasma lipid transfer particle (LTP) have been investigated by electron microscopy. LTP was found to be an asymmetric particle with two major structural features: a roughly spherical head and an elongated, hinged tail. The hinge occurs approximately at the midpoint of the tail section with the two halves forming angles ranging from 30 degrees to 180 degrees. A molecular mass estimate of 1.4 x 10(6) daltons based on the dimensions of LTP suggests that multiple copies (two or three) of each of the three LTP apoproteins exist in the native complex. Limited digestion studies of LTP suggest that apoLTP-III is less susceptible to trypsin cleavage than apoLTP-I or -II, and therefore may be less exposed to the aqueous environment. Digestion for 1 h at a 1:50 trypsin-LTP protein ratio did not alter the flotation properties of LTP or its morphological features; thus, although significant proteolysis occurred, the particle retained its overall structure. Transfer activity, on the other hand, was affected by trypsin digestion with 30 +/- 14% inhibition of LTP activity occurring upon proteolysis at a 1:50 trypsin-LTP protein ratio. Treatment of LTP with phospholipase A2 resulted in the conversion of LTP-associated phosphatidylcholine and phosphatidylethanolamine to their corresponding lyso forms. Phospholipase A2 treatment did not, however, alter the SDS-PAGE profile, transfer activity, flotation pattern, or the microscopic features of LTP. These results suggest that the products of the phospholipase reaction remain associated with the particle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies of the morphology and structure of the plasma lipid transfer particle from the tobacco hornworm, Manduca sexta. 238 Jun 35

When rat adrenal whole capsules, containing the zona glomerulosa, were incubated, addition of the protein kinase C inhibitors TMB-8 (10 mumol/l), W7, H7, polymyxin-B and sphingosine (all 1 mumol/l) was found to inhibit the steroidogenic response to trypsin. Aldosterone and 18-hydroxycorticosterone were strongly, and corticosterone moderately, affected, while the production of 18-hydroxydeoxy-corticosterone was neither stimulated by trypsin nor inhibited by the protein kinase C inhibitors. Addition of neomycin, which prevents substrate interaction with phospholipase C, also inhibited the response to trypsin, while addition of phospholipase C itself stimulated aldosterone, 18-hydroxycorticosterone and corticosterone production with the same tissue sensitivity as trypsin. Addition of phospholipase A2 had no effect. Direct assay of protein kinase C activity showed that trypsin stimulation effected the translocation of Ca2+/phospholipid-activated protein kinase C from the cytosolic to the membrane fraction. When glomerulosa tissue was incubated with [32P]ATP, and cytosolic proteins were subjected to isoelectric focusing on polyacrylamide gels, autoradiography showed that incorporation of 32P into several protein components was increased by trypsin stimulation. It was concluded that trypsin exerts its stimulatory effects on steroidogenesis by activating protein kinase C; not, however, by generating the Ca2+/phospholipid-independent fragment, but possibly by enhancing the activity of phospholipase C.
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PMID:Trypsin stimulation of aldosterone and 18-hydroxycorticosterone production by rat adrenal zona glomerulosa tissue is mediated by activation of protein kinase C. 239 25

The calpain-binding components on the plasma membrane were characterized using calpain I. 125I-labeled calpain was bound to inside-out membrane vesicles from human erythrocyte in a Ca2(+)-dependent manner, but not to right-side-out membrane vesicles. The maximum binding was observed at more than 5 microM Ca2+. The binding amount of calpain to the inside-out membrane vesicles was decreased when the vesicles were pretreated with 100 micrograms/ml of trypsin, chymotrypsin, elastase, or pronase P for 30 min at 37 degrees C, although the binding to the vesicles pretreated with 200 micrograms/ml of phospholipase A2 or C was not affected. Calpain-binding proteins in the membrane were analyzed by using a modified immunoblotting for calpain. Immunostained bands of 240, 220, 89, 72, 52, and 36 kDa were detected as the calpain-binding proteins in the native membrane. All of these bands had disappeared in trypsin-treated membrane. The disappearance of bands was dose-dependent with respect to trypsin and paralleled the reduction of binding amount of calpain to the trypsinized membrane. In calpain-treated membrane, the 240 and 36 kDa bands were retained in the blotting, though the other bands disappeared dose-dependently with respect to calpain. These results suggested that the significant component in the inner surface of plasma membrane for binding of calpain was proteinaceous and the calpain-binding proteins could be classified into two species, i.e. substrates of calpain (220, 89, 72, and 52 kDa protein) and non-substrates (240 and 36 kDa protein).
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PMID:Characterization of calpain I-binding proteins in human erythrocyte plasma membrane. 239 41

To investigate the correlation between the initial levels of serum pancreatic enzymes and the severity of acute pancreatitis, serum amylase activity, immunoreactive trypsin content, phospholipase A2 activity and immunoreactive pancreatic phospholipase A2 content were comparatively measured in 22 patients with acute pancreatitis. Serum immunoreactive pancreatic phospholipase A2 content and phospholipase A2 activity in the severe group were significantly elevated as compared with those in the group of moderate pancreatitis on the first day of onset. The elevation of the initial immunoreactive phospholipase A2 content in the severe group was far greater than that of amylase activity, trypsin content and phospholipase A2 activity. The difference between immunoreactive phospholipase A2 content and phospholipase A2 activity was, in part, due to the presence of prophospholipase A2 in severe acute pancreatitis sera, but the phospholipase A2 content measured by radioimmunoassay was still about 5 times higher than that calculated from fully activated phospholipase A2 activity by trypsin.
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PMID:Usefulness of determination of serum immunoreactive pancreatic phospholipase A2 content for early identification of severe acute pancreatitis. 243

We have analyzed the effects of aprotinin and Na2CaEDTA on phospholipase A2 activity and on the outcome of experimental pancreatitis in pigs. Hemorrhagic pancreatitis was induced in 29 piglets by infusing Na-taurocholate and trypsin into the pancreatic duct with simultaneous intravenous injection of secretin. Twelve animals serving as controls had no specific treatment. Nine animals were treated with aprotinin and eight pigs with Na2CaEDTA. Ten of the control animals died within 24 h of the induction of pancreatitis, and two of them lived for a week. In the aprotinin group three piglets died within 24 h and two died during the next day; four animals lived for a week. In the Na2CaEDTA group five animals died within 24 h and one the next day; two animals lived for a week. In all the animals serum phospholipase A2 activity increased significantly (p less than 0.01), there being no differences between the groups. In those animals that lived for a week the phospholipase A2 activities decreased on the 2nd day. This decrease was seen in both treated groups. Aprotinin prolonged the survival time of the animals. This prolongation was statistically significant (p less than 0.05, chi-square test, logrank test). Na2CaEDTA did not improve the prognosis of the animals. Neither of the drugs given influenced the serum phospholipase A2 activities during the first hours of the disease.
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PMID:Aprotinin and Na2CaEDTA in experimental hemorrhagic pancreatitis in pigs. 243 80


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